/*
 * Copyright 2011-2013 HTTL Team.
 *  
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
 *  
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package httl.spi;

import java.util.List;

/**
 * Location Switcher. (SPI, Singleton, ThreadSafe)
 *
 * @author Liang Fei (liangfei0201 AT gmail DOT com)
 * @see httl.spi.translators.CompiledTranslator#setTextFilterSwitcher(Switcher)
 * @see httl.spi.translators.CompiledTranslator#setValueFilterSwitcher(Switcher)
 * @see httl.spi.translators.CompiledTranslator#setFormatterSwitcher(Switcher)
 * @see httl.spi.translators.InterpretedTranslator#setTextFilterSwitcher(Switcher)
 * @see httl.spi.translators.InterpretedTranslator#setValueFilterSwitcher(Switcher)
 * @see httl.spi.translators.InterpretedTranslator#setFormatterSwitcher(Switcher)
 */
public interface Switcher<T> {

    /**
     * Switch's locations.
     * <p/>
     * <pre>
     * locations = ["&lt;script", "&lt;/script&gt;"]
     * </pre>
     *
     * @return locations
     */
    List<String> locations();

    /**
     * Enter the location.
     * <p/>
     * <pre>
     * filter = switcher.switchover("&lt;script", defaultFilter); // return EscapeStringFilter
     * &lt;script type="text/javascript"&gt;
     * ...
     * filter = switcher.switchover("&lt;/script&gt;", defaultFilter); // return defaultFilter
     * &lt;/script&gt;
     * </pre>
     *
     * @param location - the entered location
     * @param origin   - the origin value
     * @return the location value
     */
    T switchover(String location, T origin);

}